Attachment mechanism for dental implants

ABSTRACT

An endosseous dental implant system has an externally threaded root-formed base ( 2 ) with self-tapping flutes ( 5 ) formed into apical threads of the root-formed base for easy insertion and immediate locking in an osteotomy. The coronal portion of the base has either a male or a female self-locking tapered friction held post that includes an apical anti-rotational polygon ( 7,23 ) to lock the coronal attachment to the base once attached. The implant incorporates an esthetic biological gingival profile ( 10,11,31,32 ) to enhance inter-proximal bone attachment to the root-formed implant, which supports the surrounding papilla.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a Continuation of U.S. application Ser. No. 10/265,522, filedOct. 03, 2002.

Priority is claimed under 35 U.S.C. Section 119(e)(1) of ProvisionalApplication No. 60/326,707, filed Oct. 04, 2001.

FIELD OF THE INVENTION

This invention relates generally to artificial orthopedic implantprosthesis and more particularly, but not limited to, dental implants.

BACKGROUND OF THE INVENTION

Over the last several decades many root-formed dental implants have beendesigned to replace natural dentition and provide for both esthetic andfunctional occlusion. Although these designs provide for the functionalreplacement of natural dentition that was either lost or missing,creating the natural inter-proximal tissue between adjacent implants hasremained esthetically a restorative challenge. In fact, to maintain thesoft tissue papilla between adjacent implants requires that theunderlying inter-proximal bone area be two to three millimeters higherthan in the buccal and lingual areas. Since most dental implants are notplaced in a fresh tooth extraction site, where this physiologicalinter-proximal profile naturally occurs, grafting or countersinking theimplant may be required to obtain this inter-proximal bone between theimplants. Once the desired bone profile around the implant is surgicallyachieved, maintaining this inter-proximal bone for natural esthetics hasremained a physiological challenge.

SUMMARY OF THE INVENTION

It is an object of the present invention to overcome the limitations ofthe prior art noted above. Another object of the invention is to providea root-formed dental implant which emulates the anatomicalcharacteristics of natural dentition that can be easily manufactured andsurgically placed. Another object of the invention is to provide such animplant with an anti-rotational interlocking mechanism to drive andsecure the implant into the jaw and act as a receptor for securing aprosthetic attachment. A further object of the invention is theprovision of a single or multiple unit implant that incorporates adefined inter-dental geometry to preserve and control inter-proximalbone and papilla.

Briefly, according to a preferred embodiment of the invention, a dentalimplant comprises an elongated externally threaded base for receipt inan osteotomy, the base having a head portion formed with an estheticprofile extending around the outer periphery of the head and havingopposed buccal and lingual sides and inter-proximal zones generallyninety degrees from the center of the buccal and lingual sides. Thebuccal side, and optionally the lingual side, is formed with ascalloped, smoothly curved recess simulating the corresponding areas ofa natural tooth. Preferably, portions of the inter-proximal zones areformed with a roughened texture along a selected profile to enhance boneattachment thereto. According to a feature of the invention a male orfemale prosthetic receiving post having a self-locking taper extendsfrom the head and an anti-rotational polygonal surface portion isdisposed between the head and the post.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, advantages and details of the invention appear in thefollowing detailed description of the preferred embodiment, the detaileddescription referring to the drawings in which like reference charactersrefer to like components or structural features.

FIG. 1 is an elevational view of a single stage endosseous dentalimplant with scalloped out buccal and lingual recessed portions made inaccordance with a preferred embodiment of the invention and FIG. 1(a) isa bottom view of the end face of the base of the FIG. 1 implant;

FIG. 2 is an elevational view of a two stage endosseous dental implantwith scalloped out buccal and lingual recessed portions made inaccordance with a second preferred embodiment of the invention and FIG.2(a) is a bottom view of the base of the FIG. 2 implant;

FIG. 3 is an elevational view of a modification of the FIG. 1 singlestage endosseous dental implant having a scalloped out buccal recessedportion and FIG. 3(a) is a top view thereof;

FIG. 4 is an elevational view, partly in cross section, of amodification of the FIG. 3 two stage endosseous dental implant having ascalloped out buccal recessed portion and FIG. 4(a) is a top viewthereof;

FIG. 5 is an elevational view of a single stage endosseous dentalimplant as shown in FIG. 3 with an assembled and attached prostheticabutment shown separately in FIG. 5(a); and

FIG. 6 is an elevational view of a two stage endosseous dental implantas shown in FIG. 4 with an assembled and attached prosthetic abutmentshown separately in FIG. 6(a).

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

With reference to FIGS. 1 and 1(a), a single stage endosseous dentalimplant 1 made according to a first preferred embodiment of theinvention comprises a root-formed externally threaded base 2 and atapered interlocking coronal prosthetic attachment post 3. Incorporatedat the apex of the root-formed externally threaded base is aself-tapping thread 4 which will pull the implant downwardly during itsinitial placement. To assist in this process and to lock the implantinto place, thread 4 utilizes specially designed cutting flutes 5 tocut, form and lock the implant into place. At the foot 6 of the taperedinterlocking coronal prosthetic attachment post 3 is an anti-rotationalpolygonal surface 7 to lock the prosthetic attachment to root-formedimplant 1, once it is attached. To assure that the prosthesis remainsattached to root-formed implant 1, the male tapered post 3 uses adefined self-locking taper angle 8, shown extending from demarcationline 6, that friction locks with a female mate having a complimentaryself-locking taper. Once the prosthesis is permanently attached to thetapered post, the now single unit implant and prosthesis is secured andcannot be rotated or removed.

An esthetic coronal profile head 9 is disposed between root-formedexternally threaded base 2 and tapered interlocking coronal prostheticattachment post 3. A unique scalloped out profile 10,11 is formed inhead 9 to replicate the buccal and lingual areas of a natural tooth.These scalloped out areas comprise generally smoothly curved recesses inan annular margin of a selected thickness machined within a one to twomillimeter distance 12 to the beginning of the implant's first thread13. This one to two millimeter separation 12 allows for the clinicallyaccepted bone resorption between the implant and prosthesis connectionto end at the first thread 13 of the implant. Ninety degrees toscalloped out profiles 10,11 are enhanced profile areas for theinter-proximal zones 14, 15, which are also designed to replicate thebone in between natural dentition. These areas preferably are furthertextured at 16, by forming micro indentations or the like on the orderof 30-50 microns, as by blasting with appropriate particulate materialknown in the art, to enhance bone attachment to the implant in theseareas. Even with the standard one to two millimeter bone resorption inthese areas 14,15, the additional textured surface 16 assurespreservation and control of the inter-dental bone and papilla for thedesired esthetics. The scalloped out recesses replicate the inter-dentalgeometry of a natural tooth and assist in the maintenance of thealveolar housing and gingival soft tissue.

FIGS. 2 and 2(a) show the endosseous dental implant 17 made inaccordance with a second preferred embodiment of the invention for usewith a two stage surgical process. Implant 17 comprises a root-formedexternally threaded base 18 with an internally tapered, interlockingprosthetic attachment plug receiving bore 19. As described withreference to FIG. 1, the apex of the root-formed externally threadedbase 18 is a self-tapping thread 4 which pulls the implant downwardduring its initial placement. To assist in insertion and to lock theimplant in place, threaded base 18 utilizes specially designed cuttingflutes 5 to cut, form and lock the implant into place. Ananti-rotational polygonal surface 23 is positioned at the apex 22 of thetapered prosthetic attachment plug receiving bore 19 of the implant tolock the prosthetic attachment to implant 17 once it is attached. Toassure that the prostheses remains attached to the root-formed implantthe female tapered plug receiving bore 19 uses a defined self-lockingtaper angle 24 that friction locks with the plug of a male prostheticmate such as post 42 of FIG. 6(a) having a complimentary self-lockingtaper, to be discussed. Once the prosthesis is permanently attached inthe tapered plug receiving bore 19 the now formed single unit implantand prosthesis is secured and cannot be rotated or removed without theassistance of a specially designed removal tool, to be discussed.

FIGS. 3 and 4, respectively, show the single and two stage estheticimplant embodiments 25,26 modified to include only a single scallopedcut-out 10 formed on the buccal faces of the implants. In theseembodiments, the lingual profile 29 is at the same height or level asthe inter-proximal sides of the implants. Also lingual side surfacetexturing 31 extends above the threads to assist in tissue attachment onthis side. Since the lingual side 29 has no esthetic concerns, keepingthe material in this area of the implant improves structuralcharacteristics of the implant and simplifies the laboratory restorativechallenges. In all the implant designs, 1,17,25,26, alignment of theanti-rotational polygonal prosthetic attachment 7,23 with the scallopedout profile 10 on the buccal side of the implant 1,25,26, assist forcorrect placement of the implant in its desired rotational location.

FIGS. 5 and 6 show how the restorative attachments are made for eitherthe single or the two-stage esthetic implant embodiments. Therestorative prosthetic attachment 35, shown in FIG. 5(a) with anexemplary outer surface configuration having a generally tapered,grooved cylinder formed with a flat 35 a, is used with a single stageimplant embodiment. Prosthetic attachment 35 includes a female polygonalsurface 36 and self-locking tapered plug receiving bore 37 that engagesthe male polygonal surface 7 and friction locks on the male plug or post3 of the implant. With reference to FIG. 6, the restorative prostheticattachment 40, with an exemplary outer surface configuration includingflat 40 a, is used with the two stage implant embodiment. Prostheticattachment 40 comprises a male polygonal portion 41 and tapered plug orpost 42 that engages the female polygonal surface 23 and friction lockson the female post receiving bore 19 of the implant. In both cases, oncethe prosthetic attachment is locked onto the implant, the restorationbecomes one unit and cannot be rotated. However, in the FIG. 6embodiment, prosthetic attachment 40 is provided with internal threads40 b which allow for the use of a specially designed jack screw removaltool to apply sufficient force for removal, if desired.

Although the invention has been described with regard to specificpreferred embodiments thereof, many variations and modifications willbecome apparent to those skilled in the art. It is, therefore, theintent that the appended claims be interpreted as broadly as possible inview of the prior art to include all such variations and modifications.

1. A dental implant comprising an elongated externally threaded basehaving apical and coronal portions for receipt in an osteotomy, a headportion extending from the coronal portion of the base, and a prostheticattachment mechanism on the head for receiving a selected prosthesisincluding a generally cylindrical surface having a self-locking taper inseries with an anti-rotation polygonal surface.
 2. A dental implantaccording to claim 11 in which the lingual side of the coronal portionof the head is formed with a scalloped, smoothly curved recesssimulating the lingual area of a natural tooth.
 3. A dental implantaccording to claim 11 in which the inter-proximal zones of the apicalportion of the head is formed along a selected profile with a roughtextured outer surface to enhance bone attachment.
 4. A dental implantaccording to claim 1 in which the attachment mechanism for receiving aselected prosthesis comprises a prosthetic receiving post extending awayfrom the head portion, the post formed with the self-locking taper andthe anti-rotational polygonal surface portion is disposed between thehead portion and the prosthetic receiving post.
 5. A dental implantaccording to claim 4 further comprising a prosthesis having a postreceiving bore having opposite apical and coronal ends formed with aself-locking taper complimentary to the prosthesis receiving post and afemale polygonal surface is formed at the apical end of the basecomplimentary to the anti-rotational polygonal surface of the implant,the post receiving bore being received on the post for permanentattachment thereto.
 6. A dental implant according to claim 1 in whichthe head portion has a coronal surface and the attachment mechanismcomprises a plug receiving bore having the self-locking taper formed inthe base through the coronal surface with a self-locking taper and thefemale polygonal surface is formed at the apical end of the plugreceiving bore.
 7. A dental implant according to claim 6 furthercomprising a prosthetic attachment having a generally cylindrical plughaving an outer surface formed with a self-locking taper complimentaryto the plug receiving bore, the plug having an apical portion beyond thetaper formed as a polygonal surface complimentary to the femalepolygonal surface in the plug receiving bore and a prosthetic receivingpost extending coronally from the cylindrical plug.
 8. A dental implantcomprising an elongated externally threaded base having apical andcoronal portions for receipt in an osteotomy, a head portion extendingfrom the coronal portion of the base, a prosthetic attachment mechanismon the head portion for receiving a selected prosthesis including agenerally cylindrical surface having a self-locking taper in series withan anti-rotational polygonal surface.
 9. A dental implant according toclaim 8 in which the generally cylindrical surface having a self-lockingtaper is formed on the surface of a prosthetic receiving post extendingfrom the head and the anti-rotational polygonal surface is a malepolygonal surface disposed between the head portion and the post.
 10. Adental implant according to claim 8 in which the generally cylindricalsurface having a self-locking taper is formed on a surface defining aprosthetic plug receiving bore formed in the implant and theanti-rotational polygonal surface is a female polygonal surface.
 11. Adental implant according to claim 1 in which the head portion has anouter periphery formed with an esthetic profile extending around thebase, the head portion having an outer periphery and having opposedbuccal and lingual sides and inter-proximal zones generally ninetydegrees from the center of the buccal and lingual sides, the headportion having a peripherally extending coronal and apical portions, thebuccal side of the coronal portion of the head portion formed with ascalloped, smoothly curved recess simulating the buccal area of anatural tooth.
 12. A dental implant according to claim 7 in which atleast a portion of the cylindrical plug is tubular and is formed with aninternal threaded portion to allow for engagement with a screw removaltool to enable removal of the prosthetic attachment.